private void StockInForm_Load(object sender, EventArgs e)
 {
     _dataTable = _stockInManager.CompanyDataBindToCombobox();
     comboBoxCompanyName.DataSource = _dataTable;
     if (_dataTable.Rows.Count == 0)
     {
         comboBoxCompanyName.Text = "";
         MessageBox.Show("Company not available in record!");
     }
     //category
     _dataTable = _stockInManager.CategoryDataBindToCombobox();
     comboBoxCategoryName.DataSource = _dataTable;
     if (_dataTable.Rows.Count == 0)
     {
         comboBoxCompanyName.Text = "";
         MessageBox.Show("Category not available in record!");
     }
     TextBoxDefaultValue();
     DisplayAllRecords();
 }